Apparatus for the generation of foam for fire extinction



H. V. REED Jan. 11, 1938.

APPARATUS FOR THE GENERATION OF FOAM FOR FIRE EXTINCTION Filed July 26,1935 2 Sheets-Sheet 1 INVENTOR HEEBERTVERNON REED ATTORNEZY.

Jan. 11, 1938. H. v-. REED 2,105,264

I APPARATUS FOR THE GENERATION OF FOAM F OR FIRE EXTINCTION Filed July26, 1935 Y 2 Sheets-Sheet 2 luvcmoz HERBERT RNONREED I Patented Jan. ll,1938 mans-ms FOR. Tim GENERATION or man son Fran ax'rme'rroN HerbertVernon London, England Application July as. 1935, Serlal No. 33,272 InGreat Britain August 1, 1934 13 Claims. (cl. 261-76) runner or aseparate turbine, or in a mixing channel into which the water is ejectedfrom a 15 turbine driving a centrifugal pump which throws the foamforming substances fed thereto by gravity into the mixing channel. Thereis also the known injector method of utilizing a jet-of water flowinginto a mixing chamber to induce into the chamber the necessary. foamforming substances.

With such methods either a mechanical drive is necessary for the runner,or, if the water itself is utilized to drive the apparatus, then a gconsiderable amount of its energy is lost, and the prwent inventionseeks to avoid any of the known methods by providing a method whereinnot only does the water induce, but positively expels, by direct impact,the foam forming substances into a mixing chamber, so that the water andfoam forming substances are introduced into the said chamber separatelyand at such a velocity that they will be intimately mixed into a foamtherein, a. particular feature of this method being that the proportionof air introduced is definitely controlled. The means employed forefiecting this separate and distinct introduction of the elements of thefinal foam, whilst deriving rotary energy from a jet of water, does sowith minimum reduction of the water energy so that mamrnum pressure isavailable for expelling the foam forming substances into the mixingchamber.

The method of making foam according to the apparatus of the invention,therefore, consists in utilizing liquid pistons to induce foam formingsubstances into the piston cylinders which are of a predetermined andgreater volume than the pistons, and at the same time to sweep out thepreviously induced contents of the cylinders into one part of a mixingchamber before the pistons themselves deliver into another part of thesaid chamber.

Thus the water and foam forming substances are kept as distinct aspossible prior to delivery into the mixing chamber and due to thepredetermined volume of the piston cylinders a governed amount of foamforming substance which will be principally air or may be solely air ifthe saponin or the like has been previously added to the water-will beintroduced under pressure into 5 the mixing chamber so as to combinetherein with the water to form the foam.

The liquid pistons may be delivered on to one side of a perforatedscreen in the mixing chamber and the foam forming substances to theother 0 side of the screen, but whether the screen is used or not, thepistons will always follow the foam forming substances into the mixingchamber, the foam forming substances being expelled into a part of thechamber which may circumferen- 15 tially precede the part in which thepistons are delivered as in the rotary piston forming device to bedescribed or be in line with it where a fixed piston forming device isemployed as hereafter described. 20

The accompanying drawings illustrate various forms of apparatus for foammaking according to the present invention and in these drawings:

Fig, 1 is a longitudinal cross section through apparatus employing arotating bladed runner. 25

Fig. 2 is a front elevation of the apparatus partly in section.

Fig. 3 is a section on the line t3 of Fig. 1. Fig. 4 is a developed planof the runner and co-operating parts. 30

Figs. 5 and 6 are a plan view and a longitudinal section, respectively,illustrating an alternative form of mixing device in tube form.

Fig 'l is a longitudinal section illustrating another alternative formof mixing device in 3 tube form.

Figs. 8 and 9 are a transverse section and a side elevation, partly 'insection, respectively, illustrating another alternative form of mixingdevice. a

In the embodiment of the invention shown in Figures 1 to 4 a cylindricalcasing l is provided which houses a. runner 2 mounted on a shaft 3journaled in plain or ball bearings mounted in bosses I2, it in endplates 4, 5. l

The runner 2 consists of external and internal shroud rings or bands 6,1- between which are fitted blades 8 disposed obliquely to the axis ofthe shaft 3, the spaces between the blades opening to either side of therunner and forming passageways for the passage of liquid-pistons acrossthe runner, as will hereinafter appear. The blades 8 may alternativelybe longitudinally disposed when used with an obliquely directed liquidjet, the g internal shroud I being suitably supported from the shaft byplates.

The front end plate 4 of the casing l is fitted with a water inlet 9which may be flanged or screwed to suit any fire-hose coupling and maybe perpendicular or inclined to the surface of the end plate 4. Theinlet 9 is preferably of nozzle shape decreasing in area in thedirection of flow so that the liquid enters the spaces between therunner blades 8 at a sufficiently high velocity.

In addition, orifices or connections Iii, H are provided in the endplate 4 for the admission of air andsapo'nin or the like.

The back end plate 5 has two delivery orifices l4, l5, one H to pass theliquid pistons and the other l5 to pass the air and saponin or the like,ejected by'the pistons. Saponin or the like material may, of course,have been previously mixed with water. A long tube l6 forming a mixingchamber is attached to the end plate 5 and is divided by a perforatedmetal or wire mesh screen I'l into two compartments and terminates in anozzle [8. The screen I! may be fitted or associated with bailles I!)(see Figures 5 and 6) to ensure the passage of the liquid over thecomplete surface thereof so that the air delivered to the lower side ofthe screen is continually in contact with the liquid stream delivered tothe upper side of the screen. The tube l6 may have any.

desired shape and in Figs. 1 and 3 is illustrated as being ofsubstantially equal cross sectional area throughout its length, but isdivided by the screen I! so that the cross section of the aircompartment gradually diminishes towards the outlet l8 while the crosssection of the liquid stream compartment increases in the direction offlow so that the liquid is gradually aerated into foam. The same effectis obtained in Fig. 7 by making the perforated screen l'la conical andplacing it concentrically within the mixing tube lGa, or in Fig. 6 bydisposing the fiat perforated screen [1b substantially parallel with theupper 'side of the tube l6b which increases in width in the direction offlow. A further method is to deliver the liquid tangentially to theannular space formed between two concentric cylinders 20, 2|, (Figures8-and 9) the inner one 20 of which is perforated and open to a conduit22 to be connected to the outlet l5 of the casing through which the foamforming substances, i. e. the air and the saponin, are ejected by theliquid pistons. A conduit 24 communicates with the annular space betweenthe cylinders, and is to be connected to the outlet M of the casing I sothat the liquid pistons will be diverted spirally along theannular-space between the cylinders 20, 2| by means of bailles 23, theresulting foam being collected and delivered to the nozzle l8.

The nozzle l8 and the tube I6 may be separated from the end plate 5 andconnected thereto by two flexible hoses along which the separateingredients are conveyed.

As will be seen from Figure 4, the developed shape of the runner bladesis straight so that although the jet impinging thereon will cause therunner to rotate, the energy absorbed from the jet will be very small,which is unlike the usual water turbine or centrifugal pump wherein theblades are curved to absorb a considerable or the whole amount of thejet energy. The main purpose of the blades is to cut into the liquid jetand separate it into liquid pistons which are of considerably lessvolume than that of the spaces between the blades, and which pass withsubstantially the velocity of the jet along the blade spaces therebyexhausting the spaces to allow of the free admission of air and saponinor the like thereinto through the inlets In, H whilst expelling bydirect impact the air and saponin, previously admitted, through theoutlets ll, IS, the air and saponin first being expelled through outletl5 and the pistons themselves following through the outlet l4. Thus, inthe runner there is substantially no turbulence and no intimate mixingof the water and foam forming substances, but instead they are kept asseparate as possible within the blade spaces and only brought togetherin the mixing chamber, the high velocity of the various elementsresulting in an intimate mixture thereof and a close foam.

It will be noted from Figure 4 that each blade space comes'into registerwith the outlet IE only after it has passed the inlets Ill, H, andfurther that it is in register with the outlet when a liquid pistoncommences its travel across the particular space, i. e., when the latterregisters with the nozzle 9. Thus the obliquity of the blades is such lthat a blade space, although opening on either side of the runner, neverprovides a direct passage between the inlets l0, II and the outlet l5.During the passage across the runner of any liquid piston, the bladespace along which it is travelling will move circumferentially so thatthe liquid piston passes out through the outlet ll sub stantially in theoriginal line of the jet.

Thus, as successive blade spaces pass the outlet l5 quantities of airwill be expelled therefrom into the mixing chamber and below the screento produce the necessary volume for foam production within the mixingchamber. between a liquid piston and the volume of foam formingsubstance swept out there y is definite but subject to variation byvarying the ratio of the distance between blades to blade length andalso by varying the inclination of the blades to the runner axis.

In the above described arrangement, the liquid pistons may travelthrough the blade spaces during the time a space takes to travel fromthe commencement of outlet IE to outlet 14; the induction action of thepistons would then be indirect, the free admission of air being duetothe exhaustion of the spaces. On the other hand if the runner makes onecomplete revolution whilst a liquid piston is travelling through aspace, then as the space with the piston in it, passes the inlets "I, IIa direct induction of the foam forming substances will occur.

I claim:

1. Apparatus of the character described for making foam for fireextinguishing, comprising a casing with a runner mounted to rotatefreely therein, blades on the periphery of the runner, the spacesbetween the blades opening on either side of the runner, a nozzle on oneside of the runner for delivering a jet of liquid to the runner blades,the blades and the nozzle being disposed so that rotation of the runneris caused without substantially reducing the energy of the jet and theblades cut into the jet to form liquid pistons which sweep out thespaces between the blades, inlets on the nozzle side of the runner foradmitting foam forming substances to the blade The ratio register withsaid outlet only when the space has passed the inlets and while a liquidpiston is travelling along the particular space.

2. Apparatus for making foam for fire extinguishing comprising a casingwith a runner mounted to rotate freely therein, blades disposed on theperiphery of the runner obliquely across the runner axis and formingstraight lines when the runner is developed, the spaces between theblades opening on either side of the runner, a nozzle on one side of therunner for delivering a {ct of liquid to the runner blades which cut thejet into liquid pistons, an inlet on the nozzle side of the runner foradmitting foam forming substances to the blade spaces and separatedelivery outlets for the liquid pistons and the foam forming substancesto a mixing chamber on the opposite side: of the runner, the obliquityof the blades being such that no direct passage is provided between theinlet and outlet of the foam forming substances.

3. Apparatus of the character described, for making foam for fireextinguishing, comprising a tubular mixing chamber, a perforated screendividing the chamber longitudinally into two compartments, and means forcreating liquid pistons and causing the same to deliver foam formingsubstances to one compartment of the mixing chamber before theythemselves deliver into the'other compartment of the said chamber.

4. Apparatus of the character described, for making foam for fireextinguishing, comprising a tubular mixing chamber of substantiallyconstant cross section area through its length, a perforated screendividing the chamber longitudi-- nally into two compartments so that oneof thecompartments gradually diminishes in area towards the outlet endof the mixing chamber, and means for creating liquid pistons and causingsame to deliver foam forming substances to the compartment of graduallydiminishing area before they themselves deliver into the othercompartment of the mixing chamber,

5. Apparatus of the character described, for

making foam for fire extinguishing, comprising a making foam for fireextinguishing, comprising a casing having an inlet for liquid and anoutlet for liquid and foam forming substances, rotary means within saidcasing for dividing a stream of liquid flowing therethrough intosuccessive liquid pistons, means for the supply of foam formingsubstances in front of each liquid piston prior to its discharge fromsaid casing through said outlet, and a mixing chamber disposed toreceive liquid and foam forming substances discharged from said casingthrough said outlet.

. 7.-Apparatus as set forth in claim 6, wherein a perforated screendivides the mixing chamber into two compartments one disposed in advanceof the other as regards the direction of rotation of the liquid pistonswithin the casing so that the foam forming substances are dischargedinto one of said chambers in advance of the discharge of the liquidpistons into the other of said chambers.

8. In combination with apparatus according to claim 6, a perforatedscreen dividing the mixing chamber into two compartments, one disposedin advance of the other as regards the direction of rotation of theliquid pistons within the casing so that the foam forming substances aredischarged into one of said chambers inadvance of the discharge of theliquid pistons into the other of said chambers, and baiiles in said lastmentioned chamber to deflect the liquid from side to side during itspassage through said chamber.

9. Apparatus of the character described, for making foam for fireextinguishing, comprising a mixing chamber, rotary means for creatingsuccessive liquid pistons and causing each to deliver in front of it aquantity of air and chemical foam formant to the said chamber beforeitself discharging into the chamber, said means including a nozzledelivering a jet of liquid which is cut into the liquid pistons, an airinlet angularly preceding the nozzle and an inlet for chemical foamformant angularly preceding the air inlet.

10. Apparatusof the character described for making foam for fireextinguishing, comprising a casing housing a liquid piston formingdevice and a nozzle for delivering a jet of liquid to said device, saiddevice and nozzle being mounted for relative rotation, a series ofblades immovably mounted in said device and so disposed in relation tothe nozzle that they cause relative r'ota-. tion between themselves andthe nozzle without substantially reducing the energy of the jet, whilstcutting the jet into successive liquid pistons each of which passesaxially along and sweeps out the contents of a blade space before it,inlets for foam forming substances, arranged on the nozzle side of saiddevice so that the liquid pistons moving axially along the blade spacesinduce foam forming substances behind them,

' and a mixing chamber into which the contents of the blade spaces sweptout by the pistons and the pistons deliver in succession.

11. Apparatus of the characterdescribed for making foam for fireextinguishing, comprising a casing housing a liquid piston formingdevice tion to the nozzle that they cause relative rotation betweenthemselves and the nozzle without substantially reducing the energy ofthe jet,

whilst cutting the jet into successive liquid pistons each of whichpasses axially along and sweeps out the contents of a blade space beforeit, inlets for foam forming substances, arranged on the nozzle side ofsaid device so that the liquid pistons moving axially along the-bladespaces induce foam forming substances behind them, separate deliveryoutlets for the liquid pistons and the foam forming substances swept outby the pistons to a mixing chamber on the opposite side of said device,the outlet for the liquid pistons being arranged in advance of theoutlet for the foam forming substances.

12. Apparatus of the character described for making foam for fireextinguishing, comprising a. casing, a rurmer rotatably mounted in andabout the axis of the casing, blades on the periphery of the runnerextending across the casing between the sides thereof in which the axisof the runner is mounted, and forming spacesopen at each end, a mixingchamber having an entrance which the spaces pass in succession as therunner rotates, a nozzle for delivering a Jet of liquid to the oppositeends of the blade spaces, the blades and the nomle being disposed sothat rotation of the runher is caused without substantiallyreducing theenergy of the jet, and the blades 'cut into thejet to form liquidpistons which sweep out the contents of the blade spaces and then followthemselves into the 'mixing chamber, and inlets for admitting foamforming substances to be induced by the liquid pistons, said inletanglllarly preceding the nozzle so that the foam forming substances areinduced into the blade spaces before the said spaces open to theentrance to the mixing chamber.

13.Apparatus oi' the character described for making foam for flreextinguishing, comprising a casing having parallel side plates, a runnerrotatably mounted between the side plates, a mixing chamber having anentrance in one side plate, blades on the periphery of the runner ex- 20tending from side plate to side plate and forming spaces open at eachend and successively aromas passingthe entrance to the mixing chamber asthe runner rotates. a nozzle attached to an inlet in the other sideplate for delivering a jet of liqaid to the blade spaces as they passthe inlet,

the blades and the nozzle being disposed so that rotation of the nmneris caused without substantially reducing the energy of the jet, and theblades cut into the Jet to form liquid pistons which sweep out thecontents of the blade spaces HERBERT VERNON REED.

